The cilia-associated respiratory bacillus was first demonstrated with silver stains of sections of the respiratory tract of rats by workers in the Netherlands. It was isolated in embryonated hen's eggs by staff of Comparative Pathology Section (Inf. and Immun., Feb. 1985) as a result of efforts to diagnose and characterize chronic respiratory disease in rats from an investigator's lab at NIH. To date the agent has not been grown on cell free media. Because of its gliding, flexing motion in the absence of evidence of means of locomotion, it is believed to be a member of the group of gliding bacteria. Preliminary pathology studies indicate that infections in rats result in chronic respiratory disease.